The invention provides an over-
voltage protection method achieved by the adoption of a dry-type air-core
shunt reactor combined over-
voltage protection circuit and belongs to the field of reactor over-
voltage protection. The problems that an existing dry-type air-core
shunt reactor combined over-voltage protection device recrudesces and is poor in over-voltage protection effect are solved. The
cut-off current over-voltage protection is performed as follows, when a switch K of a
circuit breaker is
cut-off,
cut-off current over-voltage occurs, i0 is set as a
power frequency cut-off current value, U0 is set as a reactor
power frequency voltage
peak value, when t=0, the
circuit breaker generates cut-off current, a resistance-
capacitance protection device works, when the voltage on a protection device absorption
capacitor C is not larger than the
residual voltage of a
lightning arrester, the resistance-
capacitance protection device directly completes the cut-off current over-voltage protection on the reactor, when t=t0, the voltage on the protection device absorption
capacitor C is larger than the
residual voltage U1 of the
lightning arrester, the
lightning arrester makes action, when t=t1, the voltage on the protection device absorption
capacitor C is less than or equal to the
residual voltage U1 of the
lightning arrester, the
lightning arrester exits action, and the resistance-
capacitance protection device continues to complete the cut-off current over-voltage protection on the reactor. The over-voltage protection method achieved by the adoption of the dry-type air-core
shunt reactor combined over-voltage protection circuit is mainly used for reactors.